Breechloading firearms include a breechblock that is a movable component of a firearm, which closes a breech at the moment of firing. When the breech is open, a spent shell may be expelled and a new cartridge loaded into the breech. Breechblock stops are used to prevent movement of the breechblock from the opened position to the closed position. A traditional breechblock stop is disclosed in German Patent DE 196 55 169.
One functional principle of a traditional breechblock stop, in particular a breechblock stop for automatic weapons, is that a tongue of the breechblock stop extends into a region of a follower of an ammunition magazine. In the case of an emptied magazine, the follower moves the tongue up and pushes a catching surface of the breechblock stop into the path of motion of the breechblock, which stops the breechblock behind the magazine. Frictional force applied by a lock spring between the breechblock and the catching surface is sufficient to keep the breechblock stop in engagement with the breechblock even without engagement of the follower such as, for example, if the magazine has been removed. The breechblock stop is unlocked by pulling back the breechblock together with a firing lever. Then a spring moves the breechblock stop downward so that the catching surface no longer lies in the path of motion of the breechblock, and the breechblock with the firing lever can move forward very rapidly while guiding a cartridge from the magazine into the cartridge chamber—provided the magazine is not empty. Thus, after replacement of an emptied magazine for a full one, the firing lever must be operated to reset the breechblock to make the weapon ready to fire again. This type of operation costs time, usually requires that the weapon must be brought out of an aiming position, and may cause the marksman to have to move out of his cover.
German Patent DE 18 90 933 U discloses another traditional breechblock stop that has an operative control next to a trigger guard that can be operated with one finger of the shooting hand to adjust the breechblock stop from the operative position to the resting position, which in turn would release the breechblock. This breechblock stop is designed as a swiveling lever whose operative control is operated in the same direction as the trigger but in opposing orientation. With this design, an involuntary extension of the trigger finger can result in the unlocking of the breechblock stop. In such arrangement, the operative control connected to the swiveling lever runs laterally outside of the trigger guard and can thus easily and/or unintentionally be operated or damaged by outside influences (e.g. by brushing up against objects, roots, equipment or the like).